We derive a novel multiple integral representation for a generating function of the \sz-\sz correlation functions of the spin-\2 XXZ chain at finite temperature and finite, longitudinal magnetic field. Our work combines algebraic Bethe ansatz techniques for the calculation of matrix elements with the quantum transfer matrix approach to thermodynamics.
@article{arxiv.hep-th/0405089,
title = {Integral representations for correlation functions of the XXZ chain at finite temperature},
author = {F. Göhmann and A. Klümper and A. Seel},
journal= {arXiv preprint arXiv:hep-th/0405089},
year = {2009}
}